When Andy picks up Opie's football and lays it back on the bed in the next shot after Andy picks up the piggy bank, the football has changed positions to being from where Andy laid it, to the opposite side of the bed.
Opie's football changes 3 different positions to being from where Andy picks it up and lays it in front of the baseball bat, after Andy picks up the piggy bank behind Opie it is toward the far edge of the bed and when Aunt Bee enters the room, back in the middle of the bed behind the baseball bat.
Opie picks up a letter in Andy's office and tells him that it's from the FBI, except that he points to the forwarding address, which would be Mayberry, and not the return address.